Drive unit for stokers



March -2 1926.` R. A. MUNSON DRIVUUNIT Fon ys'loxrms Filed April 19'.

Patented Mar. 2, 1926.

UNITED STATES PATENT "oFricE.,

RY A. MUNSN, 0F FREEPORT, ILLINOIS.

nnivn Unia: non s'roinris,

Application filed April 19, 1924-. Serial No. 707,635.

To all whom t may concern." y

Be itknown that I, ROY A. MUNsoN, a citizen ofthe United States, residing at Freeport, in the county of Stephenson and State of Illinois, have invented certain new and useful Improvements in Drive Unitsy ice to which locomotivelstokcrs are sub-V Iected.'

The Well known type 0f stoler illustrated in the drawings, for the purpose of explaining the relation of my invention thereto, is equipped with three drive units, one being located at the head of each of the upwardly extending` screw conveyors and one beingv employed for controlling the horizontal conveyor screw associated with the transfer hopper. These drive units 'provide means for rotating the several conveyor screws in cit-her direction which the necessities of service may require. present used in such locomotive stokers the forward and reverse driving pawls are con# nected through the intervention of a coiled tension spring. The life of these tension springs is comparatively shortin service, and as they frequently break corresponding engine failures often occur. `By my inven-` tion the liability of the, stclrer'drive unitsl to fail and `thus cause engine delays is substantially eliminated, and experience has proven that drive units constructedin ac cordance with the invention i operate efficiently over very long periodswithoutrequiring attention.

`The principal feature of the invention, generally stated, consists in constructing the drive unit with a ratchet wheel driving member and a revoluble driven member, the latter being driven by the ratchet wheel through the intervention of pawl mechanism carried by the ydrive'i'i member, the said ptiwl mechanism inclu ding one or more pairs nl "ted pawls serving' a means where the retiens-it wheel may rotate the di'iivn In the drive units at member either forwardly or in reverse direction, the pawls of each pair being yieldingly connected through an interposed compression springk lwhich operates to causev the pawls to swing towards each other, and means being provided whereby either pawl of a pair may cooperatingly engage the ratchet wheel while the other pawl is disengaged from said wheel.

A further feature of the invention consists in providing the drive unit with a ratchet wheel driving member, a revoluble driven member, and pawl mechanism mounted on the driven member for cooperating with the ratchet wheel to en-able thel driven member to beyrotated either forwardly or lin reverse direction, the vpawl mechanism including a plurality of pawls yieldingly connected in one or more pairs, the means for connecting a pair of pawls comprising a coiled compression spring and a plurality of overlapping pins which slide through the spring and constitute means for compressing' the latter.

Further features of the invention residing in particular arrangements of parts and advantageous structural details will herein-V after appear and be particularly pointed out in the claims. i

In the drawings Vchosen for the purpose of illustrating the i'nventio`n,- i n Figure l is a view, partly in side elevam tion and partlyA in section, of a locomotive stoker having a drive unit embodying the invention applied thereto.

Figure 2 is a detail elevationof the drive unit, the cover of its casing being removed. v Figure 3 is a detail view on a more enlarged scale, showing the preferredjform of means for yieldingly connecting the pawls ofthe drive unit.

Figure 4 is a detail elevaticn of the relatively movable pinsforming a part of the device for yieldingly connecting the pawls.

Figure 5 is a perspective view of one of the members by which the spring controlling a pair of pawls is compressed.

As is well known, the type of locomotive stoken illustrated'in the drawings is provided with two upright elevator casings, such as l, within each of which is Aan elevator screw 2. lTheelevator screws, Q, are in communication with a transfer lipp'ei' which if* fed with. fuel by a litlriznntilly ratchet wheel 7 which is caused to` rotate first in one direction and then in the other. In the case of the drive unit for the conveyor screw .4 feeding the transfer hopper, the bac-lr and forth rotation of the ratchet wheel 7 is effected by a corresponding movement of elevator shafts` 1-2 i its conveyor screw.

the drive shaftS to one end of which the ratchet wheel is secured by means of keys 9, the opposite end of the shaft being provided with a piniony 10 which is rotated by the `stolrer engine (not shown) through the usual rack bar i 11. The corresponding ratchet wheels of the drive units for the elevator screws 2f are similarly rotated by thc which pass axially through the elevator screws 2.

Encirfcling the ratchet wheel 7 is a casing 13 which is adapted to revolve freely upon the shaft 8. vlSivotally mounted within this easing, as by ineans of pivot pins 14, are a plurality of pawls 15 and 1G, respectively, which are arranged in Vpairs and yieldingly connected. Each pair of pawls comprises a pawl 15 and a pawl 1G, the pawl 15 being` term-ed the forwardconveyor pawl by reason of the fact that it serves to communicate forward movement t0 the conveyor screw with which itis associated, and the pawl 16 being known as the reverse conveyor pawl because it communicates reversey motion. to

As shown in Fig. 2, only one of the pawls 15 and 16y of each pair is in engagement with the ratchet wheel 7 during theoperation of the drive unit; that is to sity: when the forward pawls `-cooperate with the ratchet wheel, the reverse pawls 16 are dis-` engaged from said wheel, and vice versa. The shifting of the pawls 15 and 1 6 to the positions required for imparting forward or reverse movement to the conveyor screws may be controlled by the well known form of pawl shifter 17 provided with projecting arms or fingers 18r4 which extend. lthrough slots in the revcluble casing 13 sovasto operate between thepawls of the rcspeijiife pairs. TWhen, tlielever 19, is manipulated tliepawl shifter which it controls is caused to slide and also to revolve, thus enabling the fingers 18 of the shifter to selectively disengagethe pawls from the ratchet wheel 7 Each of the, fingers 18` is preferably pro-y vided with the usiial angle slot 2O for rc-` ceiving a plug or pin 21 cari'iedby thev` cas,

ing 13, the necessary rotary movement of the pawl shifter being effected by these well known means.

The forward pawl 15 and the reverse pawl 1e of, each pair are yieldingly controlled by a compression spring 22 which encircles a pair of relatively slidable pins or bars 28. These sliding pins are preferably of identical `form and each one of them is piveta-lly connected to one of the pawls by a pin 24 which may advantageously pass through an eye 25 formed in an enlarged head 2G fashioned at one end of the pin. At its opposite end each pin is formed with a flange or shoulder 27 adapted yto form a follower for cooperating with the adjacent end of the compression spring 22 encircling both pins, the heads 26 and the respectively adjacent flanges 27 being so related that the pivot pinv openings 25 vin the said heads may be disposedcentrally in alinement with the axis of the compression spring 22. As the resultfof this construction the separation of a pai-r of pawls 15 and 16 effects a compression of the intervening spring 22. The pawl` mechanisms-is preferably protected by a suitable cover 28 rigidly eonllQGted t0 the i'evolublc kpani Casing 13 by threaded pins or bolts 29. The connection of the drive unit with the fiexibl'e drive shaft 6 is edected through this casing cover plate 2S., l

The operationv of the drive unitk will be readily understood upon reference to Fig. 2. .Yihen the-ratchet wheel 7 rotates in a counter-clockwise direction the forward kpawls 15, which are pivot-ally mounted upon the casing 13 through the pivot pins 14 cause the said casing 13 to perform a forward rotation corresponding to the similar rotation of the ratchet wheel. As the reverse pawls lflarye also mounted upon and move with the casing 13, the relative position of the pawls of each pair remains unchanged during this operation and the springV 22 is unaffected. When, however, the ratchet wheelI 7 is reversed and turns in a counterfcloclrwise direction, the springs 22 .through which the pawls are connected are compressed sufficiently to permit the forward pawls k15 to ratchet over the teeth of the wheel 7. Upon theV ratchet wheel subsequently rotating forwardly cr in couu-` ter-cloclrwise direction,y the forward pawls 15 again communicate a forward rotatioii to the casing 13. By a similar inode of operation the casing .13. is causedto rotate reversely when the reverse pawls 1G are in engagement with the ratchet wheel 7 and the forward pawls 15 are disengaged therefrom. o

1t, will be observed that-my invention not' only makes the use of 'compression springs practically possible forI the control of the pawls-of Stoker drive unitsbut also fili tion,

that the construction is such that the springs have the same amount of expansion andcompression whether the pawls are in forward or in reverse position, Jor as one pawl goes out ot engagement with the ratchet wheel 7 thek other moves into engagement, thus maintaining` the same distance between the pawls. This is a matter et importance in that the spring is therefore able to operate under the best conditions conducive to long and efficient service, not being required to 0perate at the extreme limits of its power. It will also be observed that the construction enables both pawls of a pair to be actuated by a single compression spring which is in constant operation regardless of the positions of the pawls, and that the eli1nination ot any rust or foreign matter which otherwise might accumulate and render the pawl mechanism inoperative isv thus elected. This isV advantageous since the stoler on a locomotive is usually operated in the forward position for long periods of time, and the reverse pawls of the driving mechanism are onlyv called into service occasionally when it is necessary to remove obstructions or clogs. Another advantage of my invention is that the slidable pins or members 23, which are preferably cast ot brass or steel and do not require any machine work, support the pawl controlling springs against distortion. rllie particular form of yielding control of the pawls embodied in my invention also has the added merit ot being readily applicable to stolrers of this type.

l claim l. A. drive unit for stokersA involving a ratchet wheel, means for alternately rotating said ratchet wheel inopposite directions, revolubly mounted means adapted to rotate both forwardly and in reverse direction, at least one pair et pivoted pawls whereby said last named means may be caused to rotate either forwardly or in reverse directhe pawls ot said pair being yieldingly attached to each other through the intervention ot compression spring means tending when compressed to pull the pawls toward each other, one off said pawls being adai'ited to cooperate with said ratchet wheel to drive said revolubly mounted means in one direction and the other ot' said pawls being adapted to cooperate with said ratchet wheel to drive the said revolubly mounted ineens in the reverse direction, and means for permitting either pawl oi said pair to engage and cooperate with said ratchet wheel while the other pawl is disengaged from said ratchet wheel.

2. A drive unit for stolers involving a ratchet wheel driving member, a revoluble driven member encircling said driving member, pawl-mechanism movably mounted on said driven member and adapted to cooper ate with said ratchet wheel, said pawl mecln anism including at least one pair ot pivoted pawls whereby said driven member may be caused to rotate either forwardly or in reverse direction, compression spring' means interposed between and yieldingly connecting the pawls ot said pair between the pivotal points thereotl and said ratchet wheel, said means serving to permit the tree ends of the pawls to separate relatively to each other, and means tor permitting either pawl of said pair to engage and cooperate with said ratchet wheel while the other pawl is disengaged from said ratchet wheel.

3. A revoluble driving member, a revoluble driven member, one-ot said members having ratchet teeth and the other being providcd'with pawl mechanism movably mounted thereon and cooperating' with said ratchet teeth to form a driving connection between said driving member and said driven member, said pawl mechanism including at least one pair of relatively movable pawls whereby said driven member may be caused to rotate either lforwardly or in reverse direction, compression spring means extending between and yieldingly connecting the pawls ot said pair, said spring means including relatively slidable members each pivoted to one ot said pawls, and means for permitting either pawl of said pair to engage and c0- operate with said ratchet teeth while the other pawl is disengaged from said teeth.

4. A drive unit for stolrers involving a revoluble driving member, a revoluble driven member, one of said members having ratchet kteeth and the other being provided 'with pawl mechanism cooperating with said teeth to torm a driving connection between said Idriving member and said driven member, said pawl mechanism including .at least one pair of pivoted pawls whereby said driven member may he caused to rotate either torwardly or in reverse direction, spring means interposed between and yieldingly connecting the pawls of said pair, said spring means involving a compression spring and a Vplurality of relatively movable members "for compressing said spring, each of said spring compressing members being movably connected to one ot said pawls, and means for permitting either pawl ot said pair to en gage and cooperate with said ratchet teeth while the other pawl is disengaged from said teeth.

5. A drive unit Vfor stolers involving a ratchet wheel driving member, a revoluble driven member, pawl mechanism mounted on said driven member and cooperating with said .ratchet wheel driving `member to canse said driven member to rotate either for wardly or in reverse direction, said awl mechanism including at least one pair oi pivoted pawls, spring means interposed be tween and yieldmgiy connecting the pawls drive unit for vstohers involving a of said pail", said spring means involving :i .coiled con'ipiessionsprlng and a plurality of relatively movable pin members extending through Said spring and constituting means for compressing said spring, each of Said pin members being pvotally connected te one of said pzLWls, and means for enabling either ypavvl of said pail' to engagey and c0- eperae with said ratchet wheel driving membei while the other pawl is disengaged 10 from said ratchet Wheel member.

In testimonywheieo I afx my signature.

ROY A. MUNSON, 

